The present invention relates to a fire prevention device with a heat shield plate for preventing overheat in the fixing stage of an electrophotographic copying machine and more particularly to a fire prevention device with a control mechanism permitting the heat shield plate to be shifted when necessary.
In a known fire prevention device, for example, in the Japanese Pablication of No. 12750/50 of Showa (1975), a heat shield plate is normally biased by a coil spring to close the front face of a fixing device. When in use, the front face of the fixing device is opened by removing the heat shield plate against the force of the spring by means of a solenoid. In paper jamming or power stoppage during the fixing operation, the solenoid is deenergized to release the heat shield plate thereby to automatically close the fixing device. In such a construction, it is necessary that the solenoid has a traction force enough to pull the heat shield plate resisting against the spring force and that it has a stroke large enough to open and close the fixing device. Therefore, the solenoid used must be large in size and high in cost and consumes a large electric power.